I rendered a 2000+ frame AVI movie with Blender Render and it corrupted, why?
Sorry to hear about your file; that can certainly be frustrating. I'm not sure why it became corrupted, but the best practice is always to render an image sequence. That way, if something goes wrong you can resume from where you left off. Plus, you can also open the sequence in After Effects (or any program that supports image sequences, including Blender) and re-export as an video file of your choice, if you need it to be one contiguous file. See this video as an example. I hope this helps.